In a letter dated August 2011, Interpol outlined its position to the committee, saying that it would be willing to act on a yellow notice – used for locating missing persons – if the request were to be made by the Swedish government.

According to Grenberg, the Swedish government has hitherto been reluctant to make this request, fearing that it would hamper other diplomatic efforts.

“They say that they are trying to pursue all political avenues to gain access to the Russian archives and that a yellow notice may hinder these efforts,” he said.

The timing of the request has been made to coincide with the honouring of Raoul Wallenberg in the Israeli Knesset last month in recognition of the 100th anniversary of his birth.

Wallenberg was detained by Soviet forces in 1945 and later disappeared. In 1957, the Soviet Union issued a statement saying that Wallenberg died of a heart attack in 1947, but the exact circumstances of his death remain a mystery.

The Raoul Wallenberg Honorary Citizen Committee is however hopeful that an Interpol alert may help to shed light on the mystery of the Swedish diplomat’s fate and argued in its letter to the Riksdag that it is a matter of great urgency.

“The urgency of this request cannot be overstated, since the witnesses we are attempting to find are most likely in their 80s or 90s and their life expectancies are obviously limited.”

Max Grenberg confirmed that they entertain high hopes of finding someone who can shed light on the mystery.

“There may be someone who has been carrying secrets that they want to offload,” he said.

“We hope that issuing a yellow notice will generate renewed interest in finding out about Raoul Wallenberg and what happened to him,” he added.